File that you send to us is not complete file. Size of the file 610K but it should be about 730K.
We made some modifications in HostMonitor, there is update at http://www.ks-soft.net/download/hm370c.zip
This update allows to restore tests from incomplete files. In your case you will be able to save most of tests (586), sorry about rest of tests.

Some possible reason to this error:
- system where HostMonitor is running was rebooted/shudown at the time when HostMonitor saved settings
- not enough free disk space on drive where HostMonitor is installed (in this case HostMonitor should display error message)